How to Decrease the Use of Medicated Feed Additives

Over the last 50 years, the livestock and poultry industries have seen advances in several areas including nutrition, genetics, engineering, management, and communications all of which have maximized the efficiency of growth performance and meat yield. Recently, there has been a clamor of calls for these industries to focus more attention on how animal agriculture affects the environment and overall food safety.

The global paradigm is shifting from one where there is an emphasis on productive efficiency to that of more public security. Nothing demonstrates this paradigm shift more clearly than the issues concerning the use of antibiotic growth promoters. For the past four decades, medicated feeds such as antibiotics have been used in animal agriculture to improve growth performance and protect animals from the adverse effects of pathogenic and non-pathogenic enteric microorganisms. Now, antibiotics have come under increasing scrutiny because of the potential development of antibiotic resistant human pathogenic bacteria after long use (Phillips, 1999; Ratcliff, 2000). In response, the European Union in 1997 starting banning the use of sub therapeutic levels of antibiotics to prevent disease or promote growth.

In June of 2003, McDonald’s Corp. announced that it would prohibit their poultry suppliers from using antibiotics that are important in human medicine as growth promoters in food animals after 2004, and they created a purchasing preference for companies that work to minimize antibiotic use.

Although banning antibiotic growth promoters may not be scientifically justified, the tide of public opinion is forcing animal agriculture to develop alternatives, or at least substantially reduce the amount of antibiotics used to maintain production efficiency and produce safe meat and egg products. Some of these alternatives may include significant changes in husbandry practices or the strategic use of enteric microflora conditioners, including acidifiers, probiotics and enzymes.

Exploding need for meat protein

David Bunge writing in The Wall Street Journal recently stated that food producers face a monumental task. At current consumption rates, the world would need to generate 455 million metric tons of meat annually by 2050, when the global population is expected to reach 9.7 billion, from 7.3 billion today. Given today’s agricultural productivity, growing the crops to feed all of that poultry, swine, beef and other livestock would require every acre of the planet’s cropland, according to research firm FarmEcon LLC—leaving no room for raising the grains, fruits and vegetables that humans also need. One potential solution is for companies to seek ways to breed chickens that will grow faster on less feeds and use fewer drugs to keep these animals healthy according Dr. Paul Siegel, Professor Emeritus at Virginia Tech.

Controlling gut health without antibiotics

Effective use of feed additives to manage gut health is dependent upon their mechanisms of action. Clearly, the modes of action of growth promoting antibiotics and their alternatives can differ considerably. Sub therapeutic antibiotics work in part by decreasing the microbial load in the gut, resulting in a reduction in energy and protein required to maintain and nourish the intestinal tissues. Croom et al (2000) reported that because energy required to maintain the gut accounts for about 25% of the total basal metabolic needs of an animal any reduction in gut tissue mass can have a significant impact on the amount of energy available for growth and caloric conversion efficiency. The reduced microbial load in the gut by sub therapeutic levels of antibiotics also reduces immunological stress, resulting in more nutrients partitioned toward growth and production rather than toward mechanisms of disease resistance.

In contrast, most alternative compounds do not reduce overall microbial loads in the gut and thus will not promote growth by a mechanism similar to antibiotics. Instead, they alter the gut microflora profile by limiting the colonization of unfavorable bacteria while promoting the fermentation of more favorable species. Consequently, alternatives to antibiotics promote gut health by several possible mechanisms including: altering gut pH, maintaining protective gut mucins, selection for beneficial intestinal organisms or against pathogens, enhancing fermentation acids, enhancing nutrient uptake, and increasing the humoral immune response. Strategic use of these alternative compounds will help optimize growth as long as they are used in such a manner that complement their modes of action.

Delivering acidifiers, organic acids and compounds with known bacteriostatic properties to reduce enteric diseases. Microencapsulation as a tool

Clostridia and pathogenic coliform bacteria often associated with enteric disease do not grow well in media of low pH, so any means to reduce gut pH should improve an animal’s resistance to enteric disease. Because organic acids and compounds such as Zinc Oxide have strong bacteriostatic effects, they have been used as salmonella-control agents in feed and water supplies especially for swine. Organic acid blends have also been used as acidifiers in baby pig diets to reduce enteric disease. In a 2015 Brazilian study microencapsulation of organic acid blends have been shown to increase villi height, increase the production of volatile fatty acids, increased the absorptive capacity of intestinal tissues and quantitative lesser number of piglets with diarrhea. However, the benefits of using acidic modifiers and organic acids for poultry seems to be less conclusive. Dietary acidifiers may work better in baby pig diets because they have more limited hydrochloric acid production than chicks. Moreover, dietary organic acids are easily neutralized in the duodenum unless they are delivered to the ileum and below by adsorbent vehicles. Commercial preparations of slow release microencapsulated blends of organic acids and slow release mineral compounds that deliver these non-medicated feed additives to the duodenum and beyond are being used to improve gut health in poultry and thereby lessen the use of sub therapeutic levels of antibiotics. Microencapsulation is a technology tool that can be used to deliver feed additives that improve overall gut health in swine and poultry in order to help lessen the use of sub therapeutic medicated additives in animal production.